Blue Tongue Concerns

I've had my blue tongue for almost 4 months now. In the last few weeks, he hasn't pooped at all (fed twice, feed roughly once/week), doesn't come out to bask at all, and doesn't come out of his hide at all.
Normally, I wouldn't be concerned about him being in his hide all the time, bc he's ALWAYS like that, but he always basks after eating, then hides for a few days, and walks around a bit to poop.
He hasn't been doing that at all in the past 3 weeks. I was worried after the first feed in this time span, so instead of feeding him once/week, I fed him after two weeks, then went back to once/week for his second meal. Still didn't poop, or come out at all. However, he very happily accepted food (he's a big eater).
Nothing has changed in my care for him since he started this behaviour. Feed him premium dog food, greens, blueberries, assorted veggies (usually carrot), and king worms, until a few weeks ago which I ran out of them, switching him to roaches soon.
Hot side is 35C, cool side roughly 25C.
Since I was worried, yesterday I lifted up his hide until he finally moved out of it, and he lapped up water more than usual.
I'm not sure if all this behaviour is normal for a blue tongue skink, or if perhaps he's going into shed soon, since he hasn't shed yet in the 4 months I've had him.
I've seen some people recommend feeding banana to help bowel movements. Will try that soon.
Any help is appreciated.

I've been following this recommended guide: https://bluetongueskinks.net/foodchart.html
which says to feed adults 1 to 2 times a week : o
I used to feed him multiple times a week (2-3 times), but he would only eat half his meals. now he eats 90% of his meals (which are quite big, at least a third his size) once per week
he started his shed last sunday when I fed him, and now he's looking very shiny and beautiful! : D still no poop tho

Bunch of clueless yanks. I took a look there and I'm not impressed with the advise offered by the owner of that board .

I try to feed my skinks every 2nd day ie M, W, F, Su, Tu, Th then Sa , I'd rather more smaller feeds than a huge meal once or twice a week, they aren't pythons.
I like to try to follow the Complete Critter Bluetongue Food Pyramid for my skinks.

Definitely bump up his food intake. He should be eating at least every second day. Our 2 blueys are 11 months old and we feed them a varied diet of fruits/vegetables, premium cat food, woodies, crickets and mealworms. The insects are given once a week and we alternate between fruit one day, then the next feed we give them balls made of the cat food mixed with veggies. I also add either rocket, bok choy or spinach with the veggie balls

Thank you everyone for the feedback, very late response but I have upped his food intake! Still giving him the same sized meals but more frequently, ofc he's not eating all of it, but hoping he's pooping more! He's quite chunky imo so I never realised he was being underfed for an adult!